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3. Wind / air currents
When wind is present in a rainstorm, envelopes
or cladding become increasingly subject to water
infiltration.
Besides the water being directly driven into the
cladding by the wind currents, sufficient air
pressure can cause hydrostatic pressure on the
façade and force the water upward and over the
components.
Again, proper flashings should be designed and
used to prevent this phenomenon from causing
water penetration into the structure.
The height of the flashing is determined by the
expected maximum speed and wind pressure.
All too often the height is not adequate because
of aesthetic conflicts.
This detail is too important to take a back seat to
design consideration.
The cleat will
at the bottom
prevents uplift
of the system.
Flashing used to prevent water under pressure
from entering.